Concentrations of Prostaglandins E2 and F2α and Their Relationship to Luteal function in Early Pregnant Ewes1

Gs, Lewis; Pe, Jenkins; Rl, Fogwell; Ek, Inskeep

doi:10.2527/jas1978.4761314x

Cited by 104 publications

(28 citation statements)

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“…Moreover, the PGE 2 :PGF 2a ratio is 72-fold higher in the UOV and 115-fold higher in the OA on Day 16 of pregnancy compared to that of the estrous cycle. Our present data are in agreement with several previous findings that the secretion of PGE 2 from the uterus into the UOV increases during the period of luteal resistance in early pregnancy in sheep [20,21,27,[71][72][73][74][75]. PGE 2 is a lipid-soluble mediator with a small molecular weight of 0.35 kDa, is structurally similar to PGF 2a , and can be easily transported locally from the uterus to the ovary [21] through PGT-mediated mechanisms in the UOP [52,59] and, thus, exert a luteoprotective effect through multiple mechanisms.…”

Section: Discussionsupporting

confidence: 96%

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Intraluteal Prostaglandin Biosynthesis and Signaling Are Selectively Directed Towards PGF2alpha During Luteolysis but Towards PGE2 During the Establishment of Pregnancy in Sheep1

Lee

McCracken

Stanley

et al. 2012

Biology of Reproduction

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In ruminants, endometrial prostalgandin (PG) F(2alpha) causes functional luteolysis, whereas luteal synthesis of PGF(2alpha) is required for structural luteolysis. PGE(2) is considered to be a luteoprotective mediator. Molecular aspects of luteal PGF(2alpha) and PGE(2) biosynthesis and signaling during the estrous cycle and establishment of pregnancy are largely unknown. The objectives of the present study were 1) to determine the regulation of proteins involved in PGF(2alpha) and PGE(2) biosynthesis, catabolism, transport and signaling in the corpus luteum (CL); 2) to investigate the transport of interferon tau (IFNT), PGF(2alpha), and PGE(2) from the uterus to the ovary through the vascular utero-ovarian plexus (UOP); and 3) to compare the intraluteal production of PGF(2alpha) and PGE(2) on Days 12, 14, and 16 of the estrous cycle and pregnancy in sheep. Our results indicate that luteal PG biosynthesis is selectively directed towards PGF(2alpha) at the time of luteolysis and towards PGE(2) during the establishment of pregnancy. Moreover, the ability of the CL of early pregnancy to resist luteolysis is due to increased intraluteal biosynthesis of PGE(2) and PGE(2) receptor (PTGER) 2 (also known as EP2)- and PTGER4 (also known as EP4)-mediated signaling. We also found that IFNT protein is not transported through the UOP from the uterus to the ovary; in contrast, a large proportion of endometrial PGE(2) is transported from the uterus to the ovary through the UOP. These results indicate that endometrial PGE(2) stimulated by pregnancy is transported locally to the ovary, which increases luteal PGE(2) biosynthesis and hence activates luteal PTGER2 and PTGER4 signaling, thus protecting the CL during the establishment of pregnancy in sheep.

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Section: Discussionsupporting

confidence: 96%

“…The concentrations of both PGE 2 and PGF 2a are increased in the uterine venous plasma at the time of establishment of pregnancy in sheep [10,20,21,27,[71][72][73][74]. Therefore, we measured the transport of PGF 2a and PGE 2 from the uterus to the ovary through the UOP on Days 12-16 of the estrous cycle and pregnancy.…”

Section: Discussionmentioning

confidence: 98%

Intraluteal Prostaglandin Biosynthesis and Signaling Are Selectively Directed Towards PGF2alpha During Luteolysis but Towards PGE2 During the Establishment of Pregnancy in Sheep1

Lee

McCracken

Stanley

et al. 2012

Biology of Reproduction

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“…Although embryonic signals would not appear to be essential before this time, the reports that peripheral concentrations of progesterone are elevated in cattle from the mid-luteal phase (Henricks et al, 1970;Bulman & Lamming, 1978;Lukaszewska & Hansel, 1980) indicate that the embryo may influence luteal function before the definitive maternal recognition of pregnancy occurs at around Day 15. Prostaglandin (PG) E-2 has been suggested to have a role in luteal maintenance during early pregnancy. In the pregnant ewe, concentrations of PGE-2 in ovarian arterial (Lewis et al, 1978) and utero-ovarian venous (Ellinwood et al, 1979;Silvia et al, 1984) plasma are higher than in nonpregnant ewes, and the synthesis of PGE-2 is greater in endometrial tissue derived from pregnant ewes compared to that from cyclic animals (Ellinwood et ai, 1979;Lacroix & Kann, 1982). In addition, the sheep blastocyst both secretes PGE-2 (Hyland et al, 1982;Lacroix & Kann, 1982) and metabolizes arachidonic acid into PGE-2 in vitro (Marcus, 1981).…”

Section: Introductionmentioning

confidence: 99%

Prostaglandin E-2 as a potential luteotrophic agent during early pregnancy in cattle

Shelton

Parkinson²,

Hunter³

et al. 1990

Reproduction

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Summary. Heifers slaughtered on Day 18/19 of pregnancy had significantly higher (P < 0\m=.\001) concentrations of PGE-2 (measured as its methyl oxime) in uterine flushings than did animals slaughtered on Days 6 or 12 of pregnancy, or on Days 6 or 12 of the oestrous cycle. In addition, concentrations were higher in the uterine horn ipsilateral to the corpus lueum on Days 12 (P < 0\m=.\05) and 18/19 (P < 0\ m=. \ 01) than in the contralateral horn. Incubation of dispersed luteal cells for 3 h with LH (0\ m=. \ 1 or 100 ng/ml) and/or PGE-2 (0\m=.\01\p=n-\1000ng/ml) in vitro showed no differences in basal progesterone production or in the responses to exogenous hormones between pregnant and non-pregnant cattle. However, low doses of PGE-2 (0\m=.\01\p=n-\10ng/ml) inhibited the stimulation of progesterone secretion by the lower dose of LH. These findings indicate that although PGE-2 can stimulate progesterone synthesis by luteal cells it may also have inhibitory effects, and therefore its role in pregnancy requires further definition.

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“…Nevertheless, in these species, the mechanism by which the conceptus prevents luteolysis is not yet completely elucidated. In the ewe, PGE2 or other prostanoids (Henderson et al, 1977: Lewis et al, 1978Pratt et al, 1979 ;Marcus, 1981) and a protein of trophoblastic origin (Martal et al, 1979) may be involved in corpus luteum maintenance. In bovines, Northey and French (1980) reported that the embryonic signal(s) may be given between days 15 and 17, but the chronological aspects of the interaction between the conceptus and ovary, as well as its consequences on corpus luteum function and estrous cycle length, were not completely determined.…”

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confidence: 99%

Effect of conceptus removal and intrauterine administration of conceptus tissue on luteal function in the cow

Humblot¹,

Porta²

1984

Reprod. Nutr. Dévelop.

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Summary. Two experiments were conducted to determine the day on which the bovine embryo first affects luteal function.Experiment I was to determine the sole effect of flushing the uterine lumen and involved 12 non-inseminated heifers flushed 9, 14 and 16 days after estrus (4 animals per group). The same procedure was used to remove conceptuses from 15 pregnant heifers on days 9 (n = 4), 14 (n = 5) and 16 (n = 7) after the onset of estrus. Progesterone concentrations were measured daily throughout the cycle corresponding to conceptus removal (or flushing alone) and throughout the preceding cycle. In non-inseminated animals and when the conceptuses were removed on days 9 or 14, neither the progesterone pattern nor the inter-estrous interval was altered. By contrast, when the embryo was removed on day 16, the time of luteolysis was delayed by 4 to 7 days and the heifers were observed to be in estrus 26 to 29 days after Al.In experiment 2, 21 virgin heifers were distributed over four treatment groups. Animals in groups 2 to 4 received the following treatments twice a day between day 15 and day 19 of the estrous cycle in the horn ipsilateral to the corpus luteum : group 2 (n = 3), 0,25 ml saline ; group 3 (n = 3), two 12-day-old conceptuses ; group 4 (n = 5), one 16-day-old conceptus. Progesterone concentrations were determined from day 13 of the cycle to 4 days after the following estrus. No antiluteolytic effect was found with intrauterine administration of either saline alone or day-12 embryos. In contrast, administration of day-16 conceptuses through the cervix (group 4) lengthened the estrous cycle by 6 to 7 days.The results of these experiments suggest that the antiluteolytic and/or luteotropic factor(s) originating from the conceptus is fully potent by day 16. Embryonic mortality occuring on day 16 or later may induce an extension of corpus luteum lifespan.Introduction.

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Concentrations of Prostaglandins E2 and F2α and Their Relationship to Luteal function in Early Pregnant Ewes1

Cited by 104 publications

References 0 publications

Intraluteal Prostaglandin Biosynthesis and Signaling Are Selectively Directed Towards PGF2alpha During Luteolysis but Towards PGE2 During the Establishment of Pregnancy in Sheep1

Intraluteal Prostaglandin Biosynthesis and Signaling Are Selectively Directed Towards PGF2alpha During Luteolysis but Towards PGE2 During the Establishment of Pregnancy in Sheep1

Prostaglandin E-2 as a potential luteotrophic agent during early pregnancy in cattle

Effect of conceptus removal and intrauterine administration of conceptus tissue on luteal function in the cow

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